The sum of the divisors of 25.37.53.72 is :
Sum of divisors of p1n1,p2n2,......pnnk
=p1n1+1−1p1−1,p2n2+1−1p2−1,.....pnnk−1pn−1
Required sum is = 26−12−1×38−13−1×54−15−1×73−17−1
=(26−1)×(38−1)2×54−14×73−16
The marks scored by 40 students of class IX in mathematics are given below: 81,55,68,79,85,43,29,68,54,73,47,35,72,64,95,44,50,77,64,35,79,52,45,54,70,83,62,6472,92,84,766343,54,38,73,68,52,54 Prepare a frequency distribution with class size of 10 marks.